Printer saying no paper, only from Mac and iPhone, plenty of paper, works fine on PC

[mksmags]

We have a MG6320- the printer has worked fine for both of us. However it recently stopped working from my MacBook Air and from my iPhone, but it is still working from my husband's PC. The error message says that there is no paper but there is plenty of paper in the tray. 

[fstubbsjr]

I had/have a similar problem, but here are my specifics:

1.  I have MF8580CDW, I noticed that it said no paper in tray when I tried printing from WEB.  In fact, it says the multiple paper tray.  So here is what I have concluded:  I have MAC OSX Mavericks, and Windows 8; niether one print from web because they say no paper in multiple tray.  I believe that somehow the printer program thinks that it needs a different size of paper than what is in the standard paper tray, but I have no idea how to tell it something different.  By the way, the printer work excellent printing from other applications.